On Wed, Apr 05, 2017 at 01:50:27PM +0200, Denys Vlasenko wrote: > Er.... "Change top bits ... ((47 or 56 [bits] depending on paging mode)"? > I know that's wrong and that's not what you meant to say, > but it can be read this way too. "47th" instead of "47" > would eliminate this reading, but you removed "th". > > Spell it out to eliminate any chance of confusion: > > Change top bits to match most significant bit (47th or 56th bit > depending on paging mode) in the address. > ---------------------8<----------------------- >From 5dec28ba49387ff444e447213b553506e253616d Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> Date: Wed, 5 Apr 2017 14:06:15 +0300 Subject: [PATCH] x86/asm: Fix comment in return_from_SYSCALL_64 On x86-64 __VIRTUAL_MASK_SHIFT depends on paging mode now. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> --- arch/x86/entry/entry_64.S | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 607d72c4a485..edec30584eb8 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -266,7 +266,8 @@ return_from_SYSCALL_64: * If width of "canonical tail" ever becomes variable, this will need * to be updated to remain correct on both old and new CPUs. * - * Change top 16 bits to be the sign-extension of 47th bit + * Change top bits to match most significant bit (47th or 56th bit + * depending on paging mode) in the address. */ shl $(64 - (__VIRTUAL_MASK_SHIFT+1)), %rcx sar $(64 - (__VIRTUAL_MASK_SHIFT+1)), %rcx -- Kirill A. Shutemov -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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